Continuously operating press

ABSTRACT

A continuously operating press utilizing facing endless belts for compressing chip material into chipboards, fibreboards and the like. Each of the belts is constructed as an endless belt formed of a plurality of heatable planar chain links. For conveying and directly engaging the chip material, corresponding endless steel bands envelope the chain belts. Gas flame burners are arranged in casings for directly heating a portion of the chain run at a position spaced from the engagement with the chip material. Each of the casings also include burner exhaust gas conducting channels for conducting the hot exhaust gases adjacent portions of the chain which are not impinged upon by the flame at a particular given time. Also, conduit means for the flame burner exhaust gases are provided for conducting the exhaust gases to heat the endless steel bands by way of Z-shaped channeled housings arranged at a position spaced from the casings for the flame burners and immediately adjacent the steel bands.

[ June 3, 1975 CONTINUOUSLY OPERATING PRESS Albert DeMets, Kachtem,Izegem, Belgium [73} Assignee: Bison-werke Bahre & Greten GmbH & Co. Kg,Germany [22] Filed: Mar. 8, 1973 [21] Appl. No.: 339,039

[75] Inventor:

[30] Foreign Application Priority Data Mar. 8, 1972 Germany 2211191 Apr.24, 1972 Germany 2220074 [52] US. Cl. 425/371; 100/153; 425/143;425/224; 425/335 [51] Int. Cl. 1329c 15/00 [58] Field of Search 425/143,73, 329, 371, 425/335, 224; 100/151, 154, 153;

[56] References Cited UNITED STATES PATENTS 2,289,250 7/1942 Denning264/109 2,742,951 4/1 56 Marc 425/371 X 2,784,763 3/1957 Shorts 425/143X 2,926,104 2/1960 Goetz 425/224 X 2,928,124 3/1960 Hugger 425/335 X2,967,329 l/l961 Friedland et al.. 425/430 X 2,975,470 3/1961 Snelson eta1 425/329 X 3,065,500 11/1962 Berner 425/329 X 3,325,859 6/1967Goldstein 425/371 X 3,545,370 12/1970 Caughey 425/115 X PrimaryExaminer-Robert L. Spicer, Jr. Attorney, Agent, or Firm-Craig &Antonelli 5 7 ABSTRACT A continuously operating press utilizing facingendless belts for compressing chip material into chipboards, fibreboardsand the like. Each of the belts is constructed as an endless belt formedof a plurality of heatable planar chain links. For conveying anddirectly engaging the chip material, corresponding endless steel bandsenvelope the chain belts. Gas flame burners are arranged in casings fordirectly heating a portion of the chain run at a position spaced fromthe engagement with the chip material. Each of the easings also includeburner exhaust gas conducting channels for conducting the hot exhaustgases adjacent portions of the chain which are not impinged upon by theflame at a particular given time. Also, conduit means for the flameburner exhaust gases are provided for conducting the exhaust gases toheat the endless steel bands by way of Z-shaped channeled housingsarranged at a position spaced from the casings for the flame burners andimmediately adjacent the steel bands.

26 Claims, 10 Drawing Figures CONTINUOUSLY OPERATING PRESS BACKGROUNDAND SUMMARY OF THE INVENTION The invention relates to a continuouslyoperating press for producing boards such as chipboards, fibreboards orthe like with two superimposed endless belts comprising heatable platesarticulated to one another and rotating about horizontal and parallelshafts whose facing sides are movable in the same direction particularlyby drivable feed rollers and each endless belt is enveloped by a furtherheatable endless steel band. Presses of this general type are known(U.S. Pat. Nos. 2,926,719, 2,981,307).

In order to adequately heat the heatable plates and the associatedendless steel bands covering these plates, hitherto electrically orsteamheated plates were used which were in contact with the plates ofthe endless belts to be heated or with the steel bands to be heated.This heating to an adequate temperature of the steel bands and plateswith electric power or steam is relatively expensive, even thoughheating with steam is cheaper than heating with electric power.

The present invention contemplates a more economic manner of heating ofthe endless belts and steel bands than was hitherto possible. Thepresent invention also contemplates to permit heating in a relativelyrapid manner to advantageously above 200C, as well as to increase thethroughput of the continuously operating presses.

To solve the above-discussed problems of the prior art, it is proposedaccording to a preferred embodiment of the invention to provide both theupper run of the upper endless belt and the lower run of the lowerendless belt each with at least one casing provided with at least onesuction pipe, wherein are arranged a plurality of flame burners. Theseflame burners are gas burners, each of which directly heats a portion ofthe run of the belt, the waste or exhaust gases from the burners beingled away in such a way that these gases impinge upon the endless beltalso outside the area directly heated by the gas burners. Heating theareas to be heated by gas in this way is not only much cheaper thanelectrical or steam heating but is also more effective because the wasteor exhaust gas obtained is also used for heating the areas to be heatedand namely in areas which are located in front of or behind the flameburners. In addition by the conduction of the exhaust gas in the casinga good insulation of the endless belts against cooling is obtained.

In a preferred form of the invention, each gas burner comprises achamber provided at the top with slots and surrounded by a coolingjacket wherein is arranged a supply pipe with a plurality of openingsfor a gas air mixture. Such cooling air chamber construction associatedwith the individual gas burners limits or prevents the danger that theburners would be extinguished at the relatively high temperatures ofabout 600C. The gas burners preferably are located parallel to oneanother and extend transverse to the direction of movement of theendless belts. If, for reasons of space, the casing cannot be designedso that it envelops part of the endless belt so that in practice thecasing is covered by the endless belt from above, than an adequateutilization of the exhaust gas heat is still achieved although part ofthe waste gases are led away below the parallel gas burners.

Preferably, however the casing should be designed in such a way that itenvelops at least a part of an endless belt and the part of the latteris constructed as a partition optionally with associated sealing means.In this case the corresponding endless belt is acted upon and therebyheated from one side by both the flames of the gas burners and the wastegases removed and on the other side is heated by the waste gasesremoved. In this last-mentioned arrangement it is preferred that thewalls of the casing be arranged spacedly from the portion of the endlessbelt and to provide sealing means between the side walls of the casingand the portion of the belt which extend to just before the terminalsurfaces of the casing, the suction pipe being arranged in immediateproximity of the upper side of the casing. As a result of thisconstruction of the casing, the length of the casing can be made muchlarger than the width of the endless belt area upon which the gasburners act when viewed in the direction of movement of the belt. Afterigniting the gas burner the burner exhaust gases heat the belt at pointsupon which the gas flames have not yet impinged and the portion alreadyheated by the burner flame is further heated by contacting the beltbehind the gas burners so that the heat output of the burners is fullyused.

To obtain a uniform selectable temperature in the members of the endlessbelt, the present invention further contemplates that the temperature ofthe heated plates be measured and the result of the measurements be usedvia a limit value circuit for switching on and off the burner orburners. In a preferred construction, behind the outlet point of thecasing nearest to a deflecting or reversing pulley for a respectiveendless belt, a contact plate is provided which is pivotally mountedabout a horizontal axis and is displaceable perpendicular to the planeof the plate. This contact plate has at least one heat sensor which isconnected to a thermometer. Upon reaching a selectable or predeterminedtemperature in the contact plate, some of the burners, and on reaching astill higher predetermined temperature, further or all of the burners,are disconnected or shut down. Also, on reduction of the detectedtemperature in the contact plate, part or all of the burners areconnected up again. It is preferred to provide at least two burners ineach casing to facilitate the above-discussed temperature control andoptimize heating.

Since the endless steel bands surrounding the endless belts are alsoheated by the waste gases from the gas burner, uniform temperatures overthe bands are readily obtainable.

It is further proposed by the present invention that, below the upperrun of the lower endless steel band, a housing is provided which forms aplurality of zig-zag channels and has partitions to which can besupplied the exhaust gases of the flame burner or burners heating one ofthe endless belts. This particular arrangement results in a veryeconomical heating of the lower endless steel band, even though thelength of this lower band is considerably greater than the upper endlessbelt to accommodate a material conveying function.

A more uniform temperature of the upper run of the lower endless steelband can be obtained according to the present invention by providingthat the waste gas supply connections discharge into the partialchambers of the housing associated with the endless steel band which islocated nearest to the enveloped endless belt. Although each partitionarranged in the housing can be provided at one of its ends with openingssuch as holes or slots, it is preferred that the length of eachpartition be made smaller than the width of the casing because thereby asaving in material and construction time is obtained. In both cases itpreferably should be ensured that the waste gases are led through thepartial cham bers in a zig-zag manner.

These and further objects, features and advantages of the presentinvention will become more apparent from the following description whentaken in connection with the accompanying drawings which show, forpurposes of illustration only, several embodiments in accordance withthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIGv 1. is a schematic side view of acontinuously operating press for producing fibreboards and/or chipboardswhose endless belts are each provided with two casings having flameburners or the like in accordance with the present invention;

FIG. 2 is a cross-section along the line IIII of FIG. 1;

FIG. 3 is a cross-section along the line III-III of FIG.

FIG. 4 is a plan view along the line IVIV of the casing according toFIG. 3;

FIG. 5 is a cross-section along the line V-V of FIG. 4;

FIG. 6 is an enlarged partial sectional view of a burner utilized in thepresent invention,

FIG. 7 is a side view schematically illustrating the temperaturemeasuring and gas burner switching device in accordance with the presentinvention;

FIG. 8 is a partial enlarged side view illustrating details of the entryzone of the continuously operating press of FIG. 1;

FIG. 9 is a transverse sectional view of a portion of FIG. 8, and

FIG. 10 is a plan view of a portion of the upper run of the lowerendless steel band with a housing arranged thereunder cut at the levelof the plane fixed by the axes of the waste gas feed and dischargeconnections.

DETAILED DESCRIPTION OF THE DRAWINGS The continuously operating pressshown comprises two frames 1 and 2, from each of which an endless platechain 3 and 4 is arranged in such a way that the facing chain runs 5 and6 of said plate chains form a gap therebetween which serves to shape astream of chips 21. These plate chains 3 and 4 are each envel oped by afurther respective endless band 7 or 8. These bands 7 and 8 areinterposed between the plate chains and the supply of chips 21 so as todirectly compress the chips. Endless band 8 also serves as a supplyconveyor belt to supply the stream of chip material to be compressed.The second left-hand guide roller or drum or the like provided fordeflecting the endless band 8 is not shown in the drawing. To deflect orreverse plate chains 3 and 4, use is made of respective deflection pulleys 13 and 14 or 15 and 16 having a polyangular outer contour and whichare freely rotatable about shafts 9 and 10 or 11 and 12 which arehorizontal and parallel to one another. Driving means, not shown but ofknown construction, are used to appropriately drive said chains andbands.

The facing chain runs 5 and 6 are influenced by feed rollers 17 insofaras they are associated with the upper plate chain 3. Corresponding feedrollers 18 are associated with the lower plate chain 4 which rollers 18face the upper feed rollers 17. Feed i.e. a to 17d are influenced byhydraulic means in such a way that they bring about a compression of thechip material sheet supplied. The pressure on these rollers 17a to 17dexerted is resilient and adjustable for appropriately sequentiallycompressing the chips. Feed rollers 18 arranged below feed rollers 17,17a to 17d are fixedly mounted. The diameters of the feed rollers shownare such that at all times at least two adjacent feed rollers are inworking connection with one chain plate 19 or 20; i. e. the length ofeach chain plate 19 or 20 is at least equal to double the axial spacingof respective adjacent feed rollers 17 or 18.

The runs or travel path of plate chains 3 and 4 remote from the chipmaterial sheet 21 to be compressed are heated by gas burners, to bedescribed hereinafter, arranged in respective casings 22 and 22' and/or23 and 23'. In addition, the endless steel bands 7 and 8 envelopingplate chains 3 and 4 are also heated by the waste gases of the gasburners as explained below. These bands may also be heated byelectrically heated heating plates 24 and 25 which give off their heatby contact.

Casing 23' shown schematically in FIG. 2 and associated with the lowerrun of the lower plate chain 4 is divided by partition 26 into twosuperimposed separate chambers 27 and 28. In the upper chamber 27 arearranged four gas burners 29 extending parallel to one another andtransverse to the direction of movement of plate chain 4 so that theirflames pass over the complete width of the chain plate.

As can be seen from FIG. 1 the endless steel band 8 can also be passedthrough this chamber. If the band 8 passes through chamber 23, thepartition 26 would be formed or replaced by the steel band 8 and steelband 8 would be arranged and sealed in a manner similar to the manner asshown in FIG. 3 for the casing and burners associated with the upper runof the upper plate chain 3.

Casing 23' is substantially longer than the combined width of the fourgas burners 29, as is shown by separating lines in FIG. 2. Partition 26therefore extends to positions close to the ends 30 and 31 of casing 23so that the superimposed chambers 27 and 28 are only interconnected orintereommunicated with one another in the area of the ends 30 and 31 ofthe casing. The width of the partition corresponds to the space betweenthe two side walls of the casing so that the side edges of the partitionare tightly connected with the side walls of the casing.

The waste or exhaust gases produced by the flames of the burners 29 aresucked off via a pipe 32 and part of the waste gases are removed in thedirection of arrows 33 and another portion in the direction of arrows34. As a result the underside of plate chain 4 is heated by the exhaustgases also outside the areas where the flames of gas burners 29 actdirectly on the plate chain.

Casing 22' (FIG. 3) also has gas burners 29 which are also arranged insuch a way that their flames act on the underside of the upper run ofthe upper plate chain 3. In this case casing 22' in the same way ascasing 22 envelops a portion of the plate chain 3. Since in this case,plate chain 3 is provided in the form of a partition which via sealingmeans 35 is sealed relative to the side walls of casing 22 the exhaustgases produced by the burners 29 are partially removed by suction inproximity to one end wall 30' and partially in proximity to the otherend wall 31 from the lower chamber 28' into the upper chamber 27' andfrom there via a suction pipe 32' which is located in immediateproximity of the upper side of casing 22'. This can be seen in FIG. 4.What has been stated above relative to the length of casing 23 alsoapplies for casing 22' and the other casings. Therefore in each case theheat of the waste gases is used for heating the plate chain andoptionally also for heating a steel band. The design of the gas burnerswill be explained hereinafter relative to FIGS. 5 and 6. ln casing 22'plate chain 3 is arranged spaced from all the walls of the casing. Platechain 3 subdivides with sealing or covering means 35 the inner area ofthe casing into upper chamber 27' and lower chamber 28'. In the lowerchamber are arranged the gas burners 29.

Each of the gas burners 29 comprise chambers 37 provided with slots 36wherein is arranged a feed pipe 39 for the gas air mixture having aplurality of openings 38. The slots 36 are designed in such a way thatin each of the hollow members 40 of chamber casing 41 is provided arectangular bar 42 which is fixed in the hollow members via a wire 43which envelops the bar in a spiral manner so that between bar and spiralcoils of wire 43 slots 36 are formed. It is preferred that the chambercasing 41 and therefore each gas burner is surrounded as completely aspossible by a cooling jacket 44 which is in the present case formed by atype of box 45. Cooling air is passed through the box for example bysuction at 46. Gas is supplied via a pipe 47 and air via a pipe 48 tofeed pipe 39.

Reference is made to FIG. 7 to show how the gas burners 29 are switchedon and off. On the top of plate chain 3 is placed a contact plate 49provided with a temperature sensor which is therefore located behind theoutlet point of the casing containing the respective burners 29 (saidcasing not being shown in FIG. 7). The plate 49 is guided in thevertical direction under the ac tion of a spring 50 and is pivotallymounted about a horizontal shaft 51. The contact plate 49 thereforealways rests on a plate of chain 3 even if one plate of the plate chain3 is inclined. it is preferred to arrange two guide means 52 parallel toone another which guide contact plate 49 and are jointly pivotable aboutshaft 51. The temperature determined by the temperature sensor isoperatively transferred to a measuring and indicating device 53 which isprovided with at least two contacts 54 and 55 which are open or closedif temperature rises or falls relative to a predetermined settemperature range. In the preferred arrangement illustrated in FIG. 7,as long as the temperature determined by the thermostat is under the setselectable temperature of for example 200C all the gas burners 29provided are switched on and their flames heat the plate chain 3. If, asassumed here, the temperature of 200C is exceeded then two of theburners 29 are automatically disconnected. lf also the temperature of210C is exceeded then the other two burners which are still burning arealso disconnected. The switching on of the two last disconnected burnersis brought about automatically when the temperature drops below 210C andthe two other burners when the temperature drops below 200C. Thus thetemperature of the plate chains can be controlled with relatively simplemeans.

Heating of one of the endless steel bands is explained relative to FIGS.8 to 10.

The two endless chain belts 3 and 4 are each enveloped by an endlesssteel band 7 or 8 whereof the lower endless steel band 8 has a greaterlength than the upper endless steel band 7 because it serves to supplythe chip material sheet 21 to the press. Quite apart from the fact thata longer endless steel band cools more rapidly than a shorter endlesssteel band it must in certain circumstances be cooled by supplying acooling agent to prevent a too early setting of the binder supplied tothe chip material. However this endless steel band in the working zoneof the continuously operating press must be adequately hot to ensuresetting in this working zone.

Below the upper run of the endless steel band 8 adjacent to the frontdeflection point of the endless plate chain 4 a casing or housing 56 isprovided wherein by means of partitions 57, channels 58 are providedwhich form a zig-zag channel path through housing 56. Exhaust gasesconducted from casing 22 to the housing 56 heat the steel band 8 by wayof covering wall 59 of housing 56 to the necessary temperature.

The exhaust gases emerging from casing 22 are supplied via a waste gaspipe 60 and a supply connection 61 to the part chamber of the casing 56which is closest to the endless chain belt 4. These exhaust gases passinitially into a part chamber transverse to the direction of movement ofthe endless steel band 8 (see FIG. 10) and are then passed through theother part chambers in parallel directions and led away via waste gasconnections 62. Although in the embodiment shown only three channels 58are provided it is also possible to have more than three channels.

If is preferred to connect the waste gas pipe 60 to the casing 22 whichis closest to the front deflection point of the upper endless chain belt3 because the gases leaving this casing are hottest. In similar mannerthe upper endless steel band 7 can be heated. Depending on the point atwhich the upper endless steel band 7 is heated, exhaust gases for manyflame burner casings are supplied to the zig-zag channel housing forsteel band 7 whose temperatures ensure the necessary heating. Bothendless steel bands 7 and 8 should preferably be heated substantially tothe same temperature.

It will be understood that the invention could be practiced with morethan two burner containing casings for each chain 3 and 4. Also, it willbe understood that differing numbers of and differing positioning of theexhaust gas heater housing (56) for the steel bands could be utilizedwith corresponding different conduit connections to various of theburner casings.

While I have shown and described only several preferred embodiments inaccordance with the present invention, it is to be understood that thesame is not limited thereto but is susceptible of numerous changes andmodifications as would be known to those skilled in the art given thepresent disclosure, and I therefore do not wish to be limited to thedetails shown and described herein only schematically but intend tocover all such changes and modifications.

I claim:

1. A press for producing boards such as chipboards, fibreboards, and thelike; said press comprising:

a first movable endless belt formed of heatable belt parts,

a second movable endless belt formed of heatable belt parts,

guiding and moving means for guiding and moving said first and secondbelts with respective outer surfaces of said belts in facingrelationship and moving in the same direction over a material pressingportion of the respective travel paths of said belts such that materialforming said boards can be conveyed by and compressed between said beltsalong said material pressing portion of said respective travel paths,

and heating means for heating at least one of said first and secondbelts, said heating means including at least one flame burner directinga heating flame against a portion of at least one of said belts andburner exhaust gas conducting means for directing exhaust gases fromsaid at least one flame burner against portions of at least one of saidbelts which are spaced from said portion being directly heated by saidheating flame.

2. A press according to claim 1, further comprising a first movableflexible band enclosing a portion of and movable with said first beltand a second movable flexible band enclosing a portion of and movablewith said second belt, wherein said first and second bands areinterposed between said belts over said material pressing portion of therespective travel paths thereof to directly engage said material duringpressing operations.

3. A press according to claim 2, wherein said first belt is an upperbelt, the respective material pressing portion of the travel path ofsaid first belt corresponding to a lower run of said first belt, thetravel path of said first belt including an upper run extending aboveand in the opposite direction of said lower run, wherein said secondbelt is a lower belt, the respective material pressing portion of thetravel path of said second belt corresponding to an upper run of saidsecond belt, the travel path of said second belt including a lower runextending below and in the opposite direction of said upper run of saidsecond belt, and wherein said heating means includes respective flameburners directing heating flames against a part of the upper run of saidupper belt and against a part of the lower run of said lower belt.

4. A press according to claim 3, wherein the respec tive heatable beltparts of each of said belts are relatively rigid heatable plate membersthat are articulated to one another to form said belts, and wherein saidguiding amd moving means include a pair of horizontal and parallelshafts spaced from one another for each belt, said belts being movablyguided around respective reversing pulleys rotatable about respectiveaxes of said shafts.

5. A press according to claim 4, wherein said heating means includes atleast one relatively fixed burner casing positioned adjacent each ofsaid upper run of said upper belt and said lower run of said lower belt,each of said casings containing a plurality of said flame bumers and asuction pipe forming part of said burner exhaust gas conducting means.

6. A press according to claim 5, wherein each flame burner includes achamber surrounded by a cooling jacket, said chamber having slots at thetop, a supply pipe for a gas-air mixture having a plurality of holesbeing located in said slots.

7. A press according to claim 5, wherein the flame burners in eachcasing extend parallel to one another and transverse to the direction ofmovement of the respective belt being directly heated thereby.

8. A press according to claim 6, wherein the flame burners in eachcasing extend parallel to one another and transverse to the direction ofmovement of the respective belt being directly heated thereby.

9. A press according to claim 5, wherein each casing is subdivided intotwo separate chambers intercommunicated with one another only at theends of the cas ings.

10. A press according to claim 9, wherein at least one of said casingssurrounds at least a portion of the associated belt, and wherein saidassociated belt and further sealing means form a partition between saidtwo chambers.

11. A press according to claim 10, wherein said sealing means extendalong respective opposite sides of said associated belt to positionsspaced from opposite ends of said at least one of said casings, andwherein said suction pipe is arranged in a central area of the upper ofthe two chambers in said respective casing.

12. A press according to claim 5, wherein said first and second bandsare endless steel bands which envelop the respective associated belts,and wherein said heating means includes means for directing exhaustgases from said burners directly against at least one of said bands toheat said at least one band.

13. A press according to claim 12, wherein an exhaust gas heatinghousing is positioned adjacent the travel path of one of said bands,said housing having partitions forming a plurality of zig-zag channelsinter connected with one another and with conduit means leading to anexhaust gas outlet of at least one of said casings, the burner exhaustgases being conducted by said conduit means to said housing to heat saidrespective band.

14. A press according to claim 13, wherein said conduit means opens intosaid housing at a portion of said housing which is closest to saidmaterial pressing portion of said respective travel paths.

15. A press according to claim 14, wherein the length of each partitionis less than the width of the housing.

16. A press according to claim 13, wherein said heating housing ispositioned immediately below the upper run of the second lower band, andwherein said conduit means extend from a casing containing burners forheating the upper run of said upper belt.

17. A press according to claim 16, wherein said second lower band servesas a conveyor belt for conveying material to be pressed to said materialpressing portion of said respective travel paths.

18. A press according to claim 5, wherein said reversing pulleys are ofpolygonal shape with sides thereof corresponding in length to respectivearticulated heatable plate members forming said belts.

19. A press according to claim 5, wherein movable press rollers areengageable from above with said upper belt along said materialcompressing travel path.

20. A press according to claim 1, wherein each of said at least oneflame burners includes a chamber surrounded by a cooling jacket, saidchamber having slots at the top, a supply pipe for a gas-air mixturehaving a plurality of holes being located in said slots.

21. A press according to claim 1, wherein said press is a continuouslyoperating press with said guiding and moving means including means forcontinuously guiding and moving said first and second belts.

22. A press according to claim 1, further comprising a first movableflexible band extending adjacent to and movable with said first belt,wherein said first band is interposed between said belts over saidmaterial pressing portion of the respective travel paths thereof todirectly engage said material during pressing operations, wherein anexhaust gas heating housing is positioned adjacent the travel path ofsaid first band, said housing having partitions forming a plurality ofzig-zag channels interconnected with one another and with conduit meansleading to an exhaust gas outlet of at least one burner casing of saidat least one flame burner, the burner exhaust gases being conducted bysaid conduit means to said housing to heat said first band.

23. A press according to claim 1, wherein all of said at least one flameburners are located so as to direct a heating flame against saidportions of said belts only when said portions are spaced from saidmaterial pressing portion of their respective travel paths.

24. A press according to claim 1, wherein said first belt is an upperbelt, the respective material pressing portion of the travel path ofsaid first belt corresponding to a lower run of said first belt, thetravel path of said first belt including an upper run extending aboveand in the opposite direction of said lower run, wherein said secondbelt is a lower belt, the respective material pressing portion of thetravel path of said second belt corresponding to an upper run of saidsecond belt, the travel path of said second belt including a lower runextending below and in the opposite direction of said upper run of saidsecond belt, and wherein all of said at least one flame burners arepositioned for directing heating flames against a part of the upper runof said upper belt and against a part of the lower run of said lowerbelt.

25. A press for producing boards such as chipboards, fibreboards, andthe like; said press comprising:

a first movable endless belt formed of heatable belt parts,

a second movable endless belt formed of heatable belt parts,

guiding and moving means for guiding and moving said first and secondbelts with respective outer surfaces of said belts in facingrelationship and moving in the same direction over a material pressingportion of the respective travel paths of said belts such that materialforming said boards can be conveyed by and compressed between said beltsalong said material pressing portion of said respective travel paths,

and heating means for heating at least one of said first and secondbelts, said heating means including at least one flame burner directinga heating flame against a portion of at least one of said belts, whereineach flame burner includes a chamber surrounded by a cooling jacket,said chamber having slots at the top, a supply pipe for a gas-airmixture having a plurality of holes being located in said slots.

26. A press for producing boards such as chipboards,

fibreboards, and the like; said press comprising:

a first movable endless belt formed of heatable belt parts,

a second movable endless belt formed of heatable belt parts,

guiding and moving means for guiding and moving said first and secondbelts with respective outer surfaces of said belts in facingrelationship and moving in the same direction over a material pressingportion of the respective travel paths of said belts such that materialforming said boards can be conveyed by and compressed between said beltsalong said material pressing portion of said respective travel paths,

and heating means for heating at least one of said first and secondbelts, said heating means including at least one flame burner directinga heating flame against a portion of at least one of said belts, whereinsaid first belt is an upper belt, the respective material pressingportion of the travel path of said first belt corresponding to a lowerrun of said first belt, the travel path of said first belt including anupper run extending above and in the opposite direction of said lowerrun, wherein said second belt is a lower belt, the respective materialpressing portion of the travel path of said second belt corresponding toan upper run of said second belt, the travel path of said second beltincluding a lower run extending below and in the opposite direction ofsaid upper run of said second belt, and wherein all of said at least oneflame burners are positioned for directing heating flames against a partof the upper run of said upper belt and against a part of the lower runof said lower belt.

III =l I l it

1. A press for producing boards such as chipboards, fibreboards, and thelike; said press comprising: a first movable endless belt formed ofheatable belt parts, a second movable endless belt formed of heatablebelt parts, guiding and moving means for guiding and moving said firstand second belts with respective outer surfaces of said belts in facingrelationship and moving in the same direction over a material pressingportion of the respective travel paths of said belts such that materialforming said boards can be conveyed by and compressed between said beltsalong said material pressing portion of said respective travel paths,and heating means for heating at least one of said first and secondbelts, said heating means including at least one flame burner directinga heating flame against a portion of at least one of said belts andburner exhaust gas conducting means for directing exhaust gases fromsaid at least one flame burner against portions of at least one of saidbelts which are spaced from said portion being directly heated by saidheating flame.
 1. A press for producing boards such as chipboards,fibreboards, and the like; said press comprising: a first movableendless belt formed of heatable belt parts, a second movable endlessbelt formed of heatable belt parts, guiding and moving means for guidingand moving said first and second belts with respective outer surfaces ofsaid belts in facing relationship and moving in the same direction overa material pressing portion of the respective travel paths of said beltssuch that material forming said boards can be conveyed by and compressedbetween said belts along said material pressing portion of saidrespective travel paths, and heating means for heating at least one ofsaid first and second belts, said heating means including at least oneflame burner directing a heating flame against a portion of at least oneof said belts and burner exhaust gas conducting means for directingexhaust gases from said at least one flame burner against portions of atleast one of said belts which are spaced from said portion beingdirectly heated by said heating flame.
 2. A press according to claim 1,further comprising a first movable flexible band enclosing a portion ofand movable with said first belt and a second movable flexible bandenclosing a portion of and movable with said second belt, wherein saidfirst and second bands are interposed between said belts over saidmaterial pressing portion of the respective travel paths thereof todirectly engage said material during pressing operations.
 3. A pressaccording to claim 2, wherein said first belt is an upper belt, therespective material pressing portion of the travel path of said firstbelt corresponding to a lower run of said first belt, the travel path ofsaid first Belt including an upper run extending above and in theopposite direction of said lower run, wherein said second belt is alower belt, the respective material pressing portion of the travel pathof said second belt corresponding to an upper run of said second belt,the travel path of said second belt including a lower run extendingbelow and in the opposite direction of said upper run of said secondbelt, and wherein said heating means includes respective flame burnersdirecting heating flames against a part of the upper run of said upperbelt and against a part of the lower run of said lower belt.
 4. A pressaccording to claim 3, wherein the respective heatable belt parts of eachof said belts are relatively rigid heatable plate members that arearticulated to one another to form said belts, and wherein said guidingamd moving means include a pair of horizontal and parallel shafts spacedfrom one another for each belt, said belts being movably guided aroundrespective reversing pulleys rotatable about respective axes of saidshafts.
 5. A press according to claim 4, wherein said heating meansincludes at least one relatively fixed burner casing positioned adjacenteach of said upper run of said upper belt and said lower run of saidlower belt, each of said casings containing a plurality of said flameburners and a suction pipe forming part of said burner exhaust gasconducting means.
 6. A press according to claim 5, wherein each flameburner includes a chamber surrounded by a cooling jacket, said chamberhaving slots at the top, a supply pipe for a gas-air mixture having aplurality of holes being located in said slots.
 7. A press according toclaim 5, wherein the flame burners in each casing extend parallel to oneanother and transverse to the direction of movement of the respectivebelt being directly heated thereby.
 8. A press according to claim 6,wherein the flame burners in each casing extend parallel to one anotherand transverse to the direction of movement of the respective belt beingdirectly heated thereby.
 9. A press according to claim 5, wherein eachcasing is subdivided into two separate chambers intercommunicated withone another only at the ends of the casings.
 10. A press according toclaim 9, wherein at least one of said casings surrounds at least aportion of the associated belt, and wherein said associated belt andfurther sealing means form a partition between said two chambers.
 11. Apress according to claim 10, wherein said sealing means extend alongrespective opposite sides of said associated belt to positions spacedfrom opposite ends of said at least one of said casings, and whereinsaid suction pipe is arranged in a central area of the upper of the twochambers in said respective casing.
 12. A press according to claim 5,wherein said first and second bands are endless steel bands whichenvelop the respective associated belts, and wherein said heating meansincludes means for directing exhaust gases from said burners directlyagainst at least one of said bands to heat said at least one band.
 13. Apress according to claim 12, wherein an exhaust gas heating housing ispositioned adjacent the travel path of one of said bands, said housinghaving partitions forming a plurality of zig-zag channels interconnectedwith one another and with conduit means leading to an exhaust gas outletof at least one of said casings, the burner exhaust gases beingconducted by said conduit means to said housing to heat said respectiveband.
 14. A press according to claim 13, wherein said conduit meansopens into said housing at a portion of said housing which is closest tosaid material pressing portion of said respective travel paths.
 15. Apress according to claim 14, wherein the length of each partition isless than the width of the housing.
 16. A press according to claim 13,wherein said heating housing is positioned immediately below the upperrun of the second lower band, and wherein said conduit means extend froma caSing containing burners for heating the upper run of said upperbelt.
 17. A press according to claim 16, wherein said second lower bandserves as a conveyor belt for conveying material to be pressed to saidmaterial pressing portion of said respective travel paths.
 18. A pressaccording to claim 5, wherein said reversing pulleys are of polygonalshape with sides thereof corresponding in length to respectivearticulated heatable plate members forming said belts.
 19. A pressaccording to claim 5, wherein movable press rollers are engageable fromabove with said upper belt along said material compressing travel path.20. A press according to claim 1, wherein each of said at least oneflame burners includes a chamber surrounded by a cooling jacket, saidchamber having slots at the top, a supply pipe for a gas-air mixturehaving a plurality of holes being located in said slots.
 21. A pressaccording to claim 1, wherein said press is a continuously operatingpress with said guiding and moving means including means forcontinuously guiding and moving said first and second belts.
 22. A pressaccording to claim 1, further comprising a first movable flexible bandextending adjacent to and movable with said first belt, wherein saidfirst band is interposed between said belts over said material pressingportion of the respective travel paths thereof to directly engage saidmaterial during pressing operations, wherein an exhaust gas heatinghousing is positioned adjacent the travel path of said first band, saidhousing having partitions forming a plurality of zig-zag channelsinterconnected with one another and with conduit means leading to anexhaust gas outlet of at least one burner casing of said at least oneflame burner, the burner exhaust gases being conducted by said conduitmeans to said housing to heat said first band.
 23. A press according toclaim 1, wherein all of said at least one flame burners are located soas to direct a heating flame against said portions of said belts onlywhen said portions are spaced from said material pressing portion oftheir respective travel paths.
 24. A press according to claim 1, whereinsaid first belt is an upper belt, the respective material pressingportion of the travel path of said first belt corresponding to a lowerrun of said first belt, the travel path of said first belt including anupper run extending above and in the opposite direction of said lowerrun, wherein said second belt is a lower belt, the respective materialpressing portion of the travel path of said second belt corresponding toan upper run of said second belt, the travel path of said second beltincluding a lower run extending below and in the opposite direction ofsaid upper run of said second belt, and wherein all of said at least oneflame burners are positioned for directing heating flames against a partof the upper run of said upper belt and against a part of the lower runof said lower belt.
 25. A press for producing boards such as chipboards,fibreboards, and the like; said press comprising: a first movableendless belt formed of heatable belt parts, a second movable endlessbelt formed of heatable belt parts, guiding and moving means for guidingand moving said first and second belts with respective outer surfaces ofsaid belts in facing relationship and moving in the same direction overa material pressing portion of the respective travel paths of said beltssuch that material forming said boards can be conveyed by and compressedbetween said belts along said material pressing portion of saidrespective travel paths, and heating means for heating at least one ofsaid first and second belts, said heating means including at least oneflame burner directing a heating flame against a portion of at least oneof said belts, wherein each flame burner includes a chamber surroundedby a cooling jacket, said chamber having slots at the top, a supply pipefor a gas-air mixture having a plurality of holes being locateD in saidslots.